1. Field of the Invention
The present invention relates to a method for color feature extraction and more particularly, to a method capable of precisely and rapidly extracting a color feature vector representative of the color of an image pixel contained in an image signal, and designating the color feature vector to the image pixel.
2. Description of Related Art
With the development of Internet and computer technology, application of multi-media becomes more and more popular in modern life. Unlike the conventional manner of message communication in which persons communicate with each other mostly by context, more static or dynamic image information is further attached nowadays. With the attached image information, it allows the message delivery to become more splendid and more colorful.
Image processing technique is also being improved in response to the aforementioned image signal delivery, such as image segmentation, image synthesis, image recognition, or the popular 2-Dimensional to 3-Dimensional video converting technique. With the popularity of 3D movies, the 2-Dimensional to 3-Dimensional video converting technique is promoted and becomes an even much hot topic for research. Thus, no matter for industry or for academic purpose, lots of efforts are spent in chasing 2-Dimensional to 3-Dimensional video converting technique with higher quality.
In the 2-Dimensional to 3-Dimensional video converting technique, the extraction of color feature of an image signal is deemed as a significant process. Traditionally, when desiring to extract the color feature of an image signal, a specific color space model will be selected at first, such as an HSI color space model. The selected HSI color space model has a color plane, and the color plane is segmented uniformly. Generally speaking, the color plane is segmented into five color regions and each represents different color, such as red color region, green color region, cyan color region, blue color region, and magenta color region. Additionally, the image signal being converted to this HSI color space model carries several parameters with different information. According to the parameters carried by the image signal, the image signal will be clustered to distinguished color regions of the aforementioned segmented color plane; moreover, the image signal is then determined to have what sort of color feature based upon the above process.
However, during the process of segmenting the color plane, the boundary of different color regions varies continuously, for example, the boundary varied from red color region to green color region appears to be red to greed, and therefore the vicinity of the boundary forms a fuzzy region. A corresponding point located in such a fuzzy region is difficult to be judged what exact color the corresponding point is no matter by human eye or by computer. Hence, during the process of segmenting the color plane, different result of color plane segmentation is obtained due to different sensing on color for each person.
As a result, once the color of an image pixel of an image signal is clustered to the aforementioned fuzzy region such as the boundary with color appeared to be red to greed, the color of the image pixel would possibly be judged as red by a certain person, but judged as green by another person. Hence, discrepancy occurs resulting in severely influencing the quality on color feature extraction. Therefore, how to improve the judging criterion while the color of an image pixel is clustered to fuzzy region will become an object desired to be improved in modern 2-Dimensional to 3-Dimensional video converting technique.
Accordingly, the industry needs a method for color feature extraction capable of precisely and rapidly extracting a color feature vector representative of the color of an image pixel contained in an image signal, and designating the color feature vector to the image pixel.